Fuel injector having algorithm controlled look-ahead timing for injector-ignition operation

ABSTRACT

The present invention provides an injector-ignition fuel injection system for an internal combustion engine, comprising an ECU controlling a heated catalyzed fuel injector for heating and catalyzing a next fuel charge, wherein the ECU uses a one firing cycle look-ahead algorithm for controlling fuel injection. The ECU may further incorporate a look-up table, auto-tuning functions and heuristics to compensate for the rapid rotational de-acceleration that occurs near top dead center in lightweight small ultra-high compression engines as may be used with this invention. The ECU may further ramp heat input to the injector in response to engine acceleration requests and, under such circumstances, may extend its look-ahead for up to four firing cycles.

REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 60/787,964, filed Mar. 31, 2006, the content of which isincorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The invention broadly relates to fuel injection systems and moreparticularly to an injector-ignition fuel injector for an internalcombustion engine having algorithm controlled timing forinjector-ignition operation.

BACKGROUND OF THE INVENTION

Much of the world's energy consumption is dedicated to powering internalcombustion based vehicles. Most gasoline and diesel car engines are only20-30% efficient, such that a major portion of the hydrocarbon fuels iswasted, thereby depleting global resources while producing an excessivequantity of pollutants and greenhouse gasses. As illustrated in FIG. 1(prior art), about one third of the energy used by a conventional enginemanifests itself as waste heat in the cooling system (coolant load 4)while another approximately one third of the energy goes out thetailpipe (exhaust enthalpy 2) leaving one third or less to provideuseful work (brake power 6). At the internal level, these inefficienciesare due to the fact that the conventional combustion process inside aspark ignition gasoline engine or compression ignition diesel enginetakes far too long as compared to the rotational dynamics of the pistonand crank (i.e., the power stroke of the engine).

FIG. 2 (prior art) illustrates a typical heat release profile 7 within ahigh efficiency direct injection Euro-diesel engine cycle, including anignition delay period 8, a premixed combustion phase 10, amixing-controlled combustion phase 12 and a late combustion phase 14.Combustion before about 180° of cycle rotation (top dead center) resultsin increased wasted heat load, while a large portion of the energy fromcombustion in the late combustion phase 14 (after about 200°) is wastedas exhaust heat. In other words, heat release during the time periodstarting when the piston is at the top of its stroke and rotating downabout 20 degrees (from 180° to 200°) provides the highest percentage ofuseful work. The heat release before top dead center causes pushbackagainst the rotation which manifests itself ultimately as waste heat inthe cooling jacket. Ignition must be started early in gas and dieselengines because it requires a substantial amount of time to fullydevelop as compared to the rotational timing of the engine. In the latecombustion phase 14, fuel continues to burn past the useful limit of thepower stroke, thus dumping waste heat into the exhaust system.

SUMMARY OF THE INVENTION

The present invention involves the use of one or more heated catalyzedfuel injectors for dispensing fuel predominately, or substantiallyexclusively, during the power stroke of an internal combustion engine.The injector lightly oxidizes the fuel in a super-critical vapor phasevia externally applied heat from an electrical heater or other means.The injector may operate on a wide range of liquid fuels includinggasoline, diesel, and various bio-fuels. In addition, the injector mayfire at room pressure, and up to the practical compression limit ofinternal combustion engines. Since the injector may operate independentof spark ignition or compression ignition, its operation is referred toherein as “injection-ignition”.

According to the invention, a preferred injector-ignition fuel injectionsystem for an internal combustion engine comprises an engine controlunit (ECU) controlling a heated catalyzed fuel injector for heating andcatalyzing a next fuel charge, wherein the ECU uses a one firing cyclelook-ahead algorithm for controlling fuel injection. The look-aheadalgorithm may comprise a computer software program residing on the ECU,the software program comprising machine readable or interpretableinstructions for controlling fuel injection. In operation, the algorithmcompares a current throttle input to prior engine data and determines afuel load and an estimated time to the next firing. By way of example,the prior engine data may comprise a last throttle input, an engineload, an RPM value, and an air inlet temperature. According to someembodiments, the next fuel charge comprises a mixture of approximately65% heptane, 25% cetane, and 10% ethanol by volume. Theinjector-ignition injector can fire at atmospheric pressure; however, ina preferred embodiment of the invention, the injector fires at highpressure.

According to the invention, the ECU may control various aspects ofengine operation such as (i) the quantity of fuel injected into eachcylinder per engine cycle, (ii) the ignition timing, (iii) variable camtiming (VCT), (iv) various peripheral devices, and (v) other aspects ofinternal combustion engine operation. The ECU determines the quantity offuel, ignition timing and other parameters by monitoring the enginethrough sensors including MAP sensors, throttle position sensors, airtemperature sensors, engine coolant temperature sensors and othersensors.

The fuel charge is preferably heated and catalyzed in the presence ofone or more oxygen sources, wherein the algorithm controls pre-oxidationhold time within a pressurization chamber of the fuel injector. In someembodiments, the algorithm identifies appropriate pre-oxidizer hold timesettings in an ECU database based upon a predetermined fuel mixture inuse. The ECU database contains a pre-loaded table spanning a range offuel octane ratings and oxygenator additives that may be encountered,wherein the oxygenator additives may be selected from the groupconsisting of methyl tert-butyl ether (MTBE), ethanol, other octane andcetane boosters, and other fuel oxygenator agents. The algorithmcontinuously tunes its operation over the range of fuel octane ratingsby sensing ignition delay.

The injector ignition fuel injection system set forth herein heatsliquid fuels well beyond their room pressure boiling point. However,like water, most hydrocarbon fuels and alcohols are subject to elevatedboiling point with elevated pressure so that as a liquid is heated underpressure, it will stay in liquid form well above its atmospheric boilingpoint, and will re-condense to liquid phase if it is vaporized at lowpressure and then rapidly pressurized. There is, however, a point ofpressure and temperature at which it is no longer possible to maintain aliquid phase or re-compress to a liquid phase. This is commonly calledthe critical point and includes a critical temperature and a criticalpressure. Above the critical temperature and pressure, it is no longerpossible to form a liquid, so the molecules interact in the gas phaseeven though they may be compressed beyond the density of a correspondingliquid. As per the CRC Handbook 87th Edition, the critical temperaturefor heptane (a major component of gasoline) is 512° F. and the criticalpressure is 397 psi.

The injector-ignition system of the invention utilizes oxygen reductioncatalysts which work predominately in the vapor or super-critical fluidphase. The catalyst combines available oxygen in the range of 0.1% byweight to 5% by weight with one or more components within the fuelmixture to form highly reactive, partially oxidized radicals which willvery rapidly continue to oxidize once exposed to the much richer oxygenenvironment of the main combustion chamber. The actual number of suchactive radicals required for very fast combustion (in the 100microsecond range or less) is very small, and is largely dependent onthe mean free path of the molecules and the reaction wavefrontpropagation delay within the main combustion chamber reaction zone. Forexample, at atmospheric pressure, and under the appropriate conditionsof temperature and oxygen concentration, the combustion wavefront movesat approximately the speed of sound which, under typical circumstances,is about 1 foot per millisecond. Accordingly, targeting a main chambercombustion delay of 10 microseconds indicates that these free radicalsneed to be dispersed on the order of 0.1 inches apart or closer which,based on the very large number of molecules per cubic inch, requires anexceedingly small concentration of such radicals.

Likewise, each radical that is formed in the fuel injector utilizeschemical bond energy from the fuel such that the chemical bond energy inthe main combustion chamber is reduced by that amount. It is thereforehighly advantageous to minimize the number of free radicals formed to alevel high enough to insure very high rate ignition, but low enough tominimize the degradation of the energy content of the injected fuel. Inaddition, most oxygen reduction catalysts also act as thermal crackingcatalysts, particularly when heated to elevated temperatures in the1,000° F. range and higher. Thermal cracking of the fuel in the injectoris highly undesirable because it leads to carbon formation whichinitially fouls the catalytic surface and, if allowed to continue,actually impedes the flow of fuel through the injector. In addition,short chain cracked components typically have higher auto-ignitiontemperatures and higher heats of vaporization than octane and heptane,such that under commonly occurring laboratory conditions, excessivelyheating the injector will actually increase the ignition delay beyondthe ideal situation as described above and also lead to rapid carbonformation.

In view of the above, the injector-ignition injectors described hereinoptimally utilize a highly dispersed (i.e., low concentration) oxygenreduction catalyst that has moderate activity at temperatures andpressures at which most of the fuel components are in the super-criticalphase. Nickel has been found to be one such catalyst and operates in therange of 600-750° F. at 100 bar.

In accordance with the principles of the invention, the required heatinput to the fuel may be minimized by carefully controlling the externalsource of heating in conjunction with the fuel flow rate and fuelcatalyst contact surface area, to produce an appropriate number ofradicals without allowing the catalyzed oxidation process tosignificantly contribute thermal energy to the reaction zone. Suchadditional thermal energy would rapidly lead to thermal runaway andpotentially consume all available oxygen, thereby significantly reducingthe energy content of the resultant fuel and promoting carbon formation.This is of particular concern since commercial fuels may contain 1% to10% oxygenator agents.

According to the invention, the fuel charge may be catalyzed using acatalyst selected from the group consisting of nickel,nickel-molybdenum, alpha alumina, and aluminum silicon dioxide, otherair electrode oxygen reduction catalysts, and other catalysts used forhydrocarbon cracking. In one embodiment of the invention, the fuelcharge is catalyzed using a catalyst comprising nickel with about 5%molybdenum. According to certain embodiments, the catalytic heatingtemperature is preferably between 600° F. and 750° F., most preferablyabout 720° F. In addition, injector pressure is preferably high enoughthat the fuel charge operates as a super-critical fluid at a selectedtemperature setting. The algorithm controls the fuel injector todispense the fuel charge substantially exclusively during a power strokeof the internal combustion engine.

According to one embodiment, the fuel injector runs on high octane ratedfuels, high cetane rated fuels, and mixtures of gas engine fuels anddiesel engine fuels. The ECU may include a supplemental input forreceiving fuel mixture information to accommodate a range of fuels andfuel mixtures. The fuel mixture information is provided using a directentry scheme at fueling or using an on-board analyzer which samples thefuel on board and communicates engine operating parameters to the ECU.

In accordance with the principles of the invention, preparation for anext engine firing starts immediately upon completion of a last enginefiring wherein the fuel injector is substantially empty of fuel. Thealgorithm may adjust energy input into the fuel injector such that thefuel is heated to a selected temperature more rapidly at higher throttlesettings than at lower throttle settings. Additionally, the algorithmallows up to four firing cycles of fuel to build up in the hot sectionto increase fuel heating exposure time during rapid acceleration. Wasteheat is minimized by initiating a rapid burn ignition substantially attop dead center.

According to further embodiments of the invention, the ECU provides aninjector fire signal approximately 1-3 milliseconds before top deadcenter to offset mechanical delay when the engine is rapidlydecelerating due to compression braking. Additionally, the ECU mayinclude an engine look-up table which corrects for engine decelerationover a predetermined operating map including RPM, engine load, andengine load trend. The engine look-up table may be pre-loaded with alearning algorithm to measure the error in predicted top dead centerversus actual top dead center for a particular class of engine geometry.Additionally, the engine look-up table may be dynamically adjusted inoperation through use of a learning algorithm which continually adjuststable entries by computing the difference between an injection pinlocation indicator and an absolute top dead center indicator. Theadjustment may be further refined using knock sensor input, or using anin cylinder pressure sensor which detects absolute fire position versustop dead center. According to additional embodiments, the ECU utilizespattern recognition heuristics to fine tune ignition delay drift due tocompression braking, wherein pattern recognition heuristics provide forthe identification of a steady state throttle and load condition, sothat ignition timing drift can be isolated from other variableparameters.

Another embodiment of the invention features an injector-ignition fuelinjection system for an internal combustion engine, comprising an ECUcontrolling a heated catalyzed fuel injector for heating and catalyzinga next fuel charge, wherein the ECU uses a one firing cycle look-aheadalgorithm for controlling fuel injection, wherein the heated catalyzedfuel injector comprises an input fuel metering system for dispensing anext fuel charge into a pressurizing chamber, a pressurization ramsystem including a pressurization ram for compressing the fuel chargewithin the pressurizing chamber, wherein the fuel charge is heated inthe pressurization chamber in the presence of a catalyst, and aninjector nozzle for injecting the heated catalyzed fuel charge into acombustion chamber of the internal combustion engine.

In the above-described system, preparation for a next engine firingstarts immediately upon completion of a last engine firing. Uponcompletion of the last engine firing, the fuel injector is substantiallyempty of fuel, the pressurization ram is in a full displacementposition, and the injector nozzle is closed. A next firing cycleinvolves retracting the pressurization ram, which allows the input fuelmetering system to dispense an aerosol of liquid fuel into thepressurization chamber. The pressurization ram then pressurizes the fuelin a two step cycle, including protecting the fuel injector while thefuel is heating and vaporizing, and pressurizing the fuel to a targetinjection pressure and temperature. The fuel is vaporized to reach thetarget injection pressure and temperature. During operation, theinjector nozzle opens after a pre-determined hold time and thepressurization ram pushes the fuel charge into the combustion chambersuch that the pressurization ram reaches a full displacement position.In some embodiments, the pre-determined hold time is back projected froma next top dead center event.

BRIEF DESCRIPTION OF THE DRAWINGS

The FIG. 1 (prior art) is a schematic diagram that illustrates theinefficiencies in a conventional combustion process inside a sparkignition gasoline engine or a compression ignition diesel engine;

FIG. 2 (prior art) is a schematic diagram that illustrates a typicalheat release profile within a high efficiency direct injectionEuro-diesel engine cycle;

FIG. 3 is a schematic diagram that illustrates the difference betweenignition in a conventional gas engine and ignition in an internalcombustion engine having a fuel injector in accordance with theprinciples of the invention;

FIG. 4 is a schematic diagram illustrating a heat release profile for aninternal combustion engine having a fuel injector in accordance with theprinciples of the invention;

FIG. 5A depicts a combustion chamber for the internal combustion engineof the invention including a fuel injector mounted substantially in thecenter of the cylinder head;

FIG. 5B is a schematic diagram illustrating an exemplary ECU forcontrolling fuel injection in accordance with the principles of theinvention;

FIG. 5C is a schematic diagram illustrating wireless communicationbetween the ECU of FIG. 5B and a conventional gasoline pump fuel nozzle;

FIG. 6 depicts a preferred heated catalyzed injector-ignition fuelinjector constructed in accordance with the principles of the presentinvention;

FIG. 7 is a sectional view of the heated catalyzed injector-ignitionfuel injector of FIG. 6 showing the fuel inlet and outlet subsystems;

FIG. 8A is a sectional view of the fuel injector of FIG. 6, wherein theram is in a full displacement position, whereas FIG. 8B is a sectionalview of the fuel injector of FIG. 6, wherein the ram is in a fullyretracted position for allowing liquid fuel to enter the pressurizationchamber; and

FIG. 9 is a sectional view of an alternative fuel injector of theinvention comprising a linear fuel injector.

DETAILED DESCRIPTION

In the following paragraphs, the present invention will be described indetail by way of example with reference to the attached drawings.Throughout this description, the preferred embodiment and examples shownshould be considered as exemplars, rather than as limitations on thepresent invention. As used herein, the “present invention” refers to anyone of the embodiments of the invention described herein, and anyequivalents. Furthermore, reference to various feature(s) of the“present invention” throughout this document does not mean that allclaimed embodiments or methods must include the referenced feature(s).

In accordance with the principles of the present invention, aninjector-ignition fuel injection system for an internal combustionengine is provided, the system comprising an engine control unit (ECU)controlling a heated catalyzed fuel injector for heating and catalyzinga next fuel charge, wherein the ECU uses a one firing cycle look-aheadalgorithm for controlling fuel injection.

Detonation comprises an alternative form of combustion that provides anextremely fast burn and is commonly manifested as the familiar knock inmistuned car engines. Conventional internal combustion engines placetheir entire fuel load in the cylinder before ignition. Detonationcauses a significant portion of the entire fuel load to ignite in a fewmicroseconds, thus producing an excessive pressure rise which can damageengine parts. These conditions typically occur in an uncontrolledfashion in mistuned engines, causing the fuel to detonate at some timeother than appropriate for power stroke production. In addition, thistype of detonation is dependent on an ignition delay to compress the airsupply and vaporize the fuel.

Referring to FIG. 3, a schematic diagram is provided that illustratesthe difference between slow combustion in a conventional gas engine andfast combustion including detonation in an internal combustion enginehaving a fuel injector in accordance with the principles of theinvention. In particular, ignition in a conventional gas enginesubstantially occurs in a slow burn zone 20 at low fuel density. Bycontrast, in an internal combustion engine having a fuel injector asdescribed herein, ignition substantially occurs in a fast burn zone 22at high fuel density. In the fast burn zone 22, a leading surface of thefuel charge is completely burned within a matter of microseconds.

Referring to FIG. 4, a schematic diagram is provided that illustrates aheat release profile 26 for an internal combustion engine having a fuelinjector in accordance with the principles of the invention.Particularly, the heat release profile 26 is superimposed over thetypical heat release profile 7 of the direct injection Euro-dieselengine cycle depicted in FIG. 2, the heat release profile 7 including anignition delay period 8, a premixed combustion phase 10, amixing-controlled combustion phase 12, and a late combustion phase 14.In contrast to the direct injection Euro-diesel engine, the fuelinjector set forth herein (having heat release profile 26) preciselymeters instantly igniting fuel at an appropriate crank angle for optimalpower stroke production. Specifically, the fuel injector dispensesinstantly burning fuel in a precise fashion substantially exclusivelyduring the power stroke, thereby greatly reducing both front end(cooling load) and back end (exhaust enthalpy) heat losses within theengine. According to some embodiments of the invention, conventional lowoctane pump gasoline is metered into the fuel injector, wherein the fuelinjector heats, vaporizes, compresses and mildly oxidizes the fuelcharge, and then dispenses it as a relatively low pressure gas columninto the center of the combustion chamber.

Referring to FIG. 5A, a combustion chamber 28 for an internal combustionengine is illustrated comprising a conventional automotive diesel highswirl high compression combustion chamber. Particularly, the combustionchamber 28 includes a heated catalyzed injector-ignition fuel injector30 of the invention mounted substantially in the center of the cylinderhead 32. As a fuel column 36 of hot gas is injected into the combustionchamber 28, its leading surface 37 auto-detonates, which radiallydispenses the fuel column 36 into a swirl 38 pattern in a directionindicated by arrows 40. The leading surface 37 represents the detonationinterface, while the swirl 38 represents dispersed gas and air yieldingfast lean burn. Such a combustion chamber configuration provides afairly conventional lean burn environment, wherein 0.1% to 5% of thefuel has been pre-oxidized in the fuel injector 30 by use of hightemperature and pressure. The fan-shaped element 41 of FIG. 5A depictsthe rotational movement of the radially expanding fuel charge it swirlswithin the combustion chamber 28. The fuel charge may expandsymmetrically or may be comprised of one or more offset rows of jets,each row including a plurality of jets (e.g., four jets). As would beappreciated by those of skill in the art, any number of jets may beformed without departing from the scope of the invention.

With further reference to FIG. 5A, pre-oxidation within the heatedcatalyzed fuel injector 30 may involve surface catalysts on the injectorchamber walls and oxygen sources including standard oxygenating agents.Optionally, pre-oxidation may further involve a small amount ofadditional oxygen, e.g., from air or the last firing in the form ofrecirculated exhaust gas. This slightly oxidized fuel contains radicalsin the form of RO₂. and ROOH., which are highly reactive, partiallyoxidized, cracked hydrocarbon chains from the initial fuel. Thus, theinjected fuel provides relatively low temperature auto-ignition siteswithin the dispensed fuel column 36 which supports the initiation ofsurface auto-detonation and subsequent lean burn within a temperatureand pressure range compatible with conventional automotive engineconstruction materials.

Referring to FIG. 5B, an exemplary ECU 45 for controlling fuel injectionand other engine operations is illustrated. Specifically, the ECU 45includes an injector timing routine 47 which determines when theinjector will fire, an injection firing routine 49 which sequences themechanical operation of the injector subsystems, a temperature control51 for controlling an injector heating drive, and other ECU routines 53controlling other engine and vehicle outputs. In operation, theinjection timing routine 47 receives inputs from a crank position andRPM sensor, an injector pin position sensor, and an engine knock sensor.The injection timing routine 47 outputs the timing routine to theinjection firing routine 49, which controls an injector fuel inlet (1per cylinder), an injector high pressure pump drive (1 per cylinder insome configurations), and an injector pin drive (1 per cylinder). Theinjector firing routine 49 may further receive input from the ECU enginethrottle routine and various other engine sensor routines as typicallyfound on modern gasoline and diesel engines to adjust for changes intemperature, pressure, humidity, engine load, fuel quality, engine wear,and other variables. The temperature control 51 of the ECU 45 receivesinputs from an injector temperature sensor and, in turn, controls theinjector heating drive. The various other ECU routines 53 receive inputsfrom various other engine and vehicle sensors, such that the ECUroutines 53 control various additional engine and vehicle outputs.

Referring to FIG. 5C, further embodiments of the invention feature asmart fueling system 55 for a multi-fuel vehicle having an advancedvariable cycle engine and an ECU (e.g., the ECU 45 of FIG. 5B) incommunication with a conventional filling station fueling pump 57 by wayof wireless serial communications links 59, 61 that may be co-locatedwith the ECU 45 and the fueling pump 57, respectively. The system 55 isemployed to offer customers one or more optimized fuel blends forrefueling their multi-fuel vehicles. This information may be shown on anin-dash display 63 in communication with the ECU 45 as well as on thesales display 83 of the fuel station pump 57. The user may make a fuelselection based on buttons, touch sensitive areas or other conventionalinput means on display 83 and, optionally, on the in-dash display 63.Data exchange between the ECU 45 and the fueling pump 57 may be providedby any conventional wireless communication technology such as magneticinduction, optical communications, or low power RF. In operation, theECU 45 communicates to the fueling pump 57 the precise fuel mixture andamount of fuel in the vehicle's tank 81, which is determined by way of afuel tank sensor 65. In response, a fueling pump controller 67calculates appropriate refueling mixtures that are compatible with theremaining fuel and the vehicle's operational capabilities, and offersthe customer one or more refueling options based upon various fuels 69(or mixtures thereof) that are for sale. Upon purchase the appropriatefuel or fuel mixture is pumped (via fuel pump 73) through pump valves 77and injected into the tank 81 via fueling pump nozzle 79.

With further reference to FIG. 5C, the refueling options may be basedupon selectable parameters including cost and performance, wherein thefilling station fueling pump 57 blends and dispenses the fuel based uponthe customer's selections. In the illustrated embodiment, the fillingstation fueling pump 57 includes a point of sale display 83 and anassociated means for user input. The ECU 45 determines actual fuelperformance during combustion using engine performance under load(engine RPM), load sensors and knock sensors. Additionally, the ECU 45may be configured to maintain a log of all fuel loadings including theprecise mixture of fuels and the amount pumped into the tank, fuelconsumption, observed performance, and chronological climate conditionssuch as temperature, barometric pressure, altitude and humidity.

The advanced variable cycle engine may be adapted to operate with a widerange of fuels including, but not limited to, conventional gasoline,diesel, ethanol, methanol, other alcohols, biodiesel, and plant extractsoptionally including blended water content. The vehicle may be equippedwith a single fuel tank, or multiple fuel tanks for accommodatingincompatible fuel blends. Purchasing decisions at the pump may be basedupon multiple factors such as the most cost effective fuel supplyavailable, the fuel mixture remaining in the fuel tank, and anticipateddriving conditions including weather and altitude. The vehicle iscapable of dynamically adapting to various fuel mixtures under controlof the ECU.

According to further embodiments of the invention, the heated catalyzedfuel injector 30 may be utilized in an injector engine that runs on abio-renewable flex fuel. By way of example, the flex fuel may compriseplant extract oil (e.g., soybean oil, canola oil, algae and planktonextractions) that is mixed with small quantities of gasoline and/orethanol. The resultant mixture may comprise a zero net carbonbio-renewable flex fuel suitable for use with for ultra-high compressionengines equipped with heated, catalyzed direct-injectors. Such a zeronet carbon fuel produces no net carbon in the Earth's biosphere whenburned because the carbon present in the plant material is from capturedcarbon dioxide in the Earth's atmosphere as part of the normalphotosynthesis process. According to the invention, raw plant oils aremixed with ethanol in conjunction with a small quantity of conventionalgasoline (or other mixtures of linear hydrocarbons in the range of C5 toC10. By way of example, the mixture may contain 65% plant oil (byweight) mixed with 25% gasoline and 10% ethanol. The mixture is stableand does not separate into its various constituents under normalhandling conditions. In addition, the mixture has a freezing point below0° F. and is resistant to biological attack.

The fuel mixture described above is composed of high cetane plant oilwhich ignites well under the high compression of a diesel engine, aswell as relatively high octane hydrocarbons (heptane) and ethanol, whichperform well in low compression spark ignition engines, but do nottypically perform well in compression ignition engines. For example, ahigh compression engine (e.g., 20 to 1) equipped with an injector thatis both heated and contains oxygen reduction catalysts runs veryeffectively on the above-identified mixture. In addition, the heatingdirectly accommodates the higher viscosity of the plant oils and alsofacilitates starting in cold environments. Additionally, the combinationof heating and oxygen reduction catalysts attacks the oxygen bound inthe ethanol to lightly oxidize the fuel mixture such that it burns veryrapidly in the combustion chamber independent of the octane and cetaneratings of its components.

The above-described bio-renewable flex fuels are preferably catalyzed inthe gas phase or super-critical phase only (as opposed to the liquidphase). In addition, the catalyzed smoldering fuel is preferablyinjected using a high pressure nozzle dispersal system at 100 bar ormore, in contrast to conventional pre-chamber systems which rely onrelatively slow and inefficient gas diffusion between the chambers or alow pressure intake manifold port valve.

According to the invention, the heated catalyzed fuel injector 30 may bemounted in place of a conventional direct diesel injector on a smallautomotive diesel engine. The converted diesel engine may run ongasoline and operate at high compression ratios in the range of 16:1 to25:1. To achieve the high compression ratios, the engine preferablyemploys compression heating rather than a conventional spark ignition.As would be appreciated by those of ordinary skill in the art, the fuelinjector of the invention may be used with other fuels such as dieselfuel and various mixtures of cetane, heptane, ethanol, plant oil,biodiesel, alcohols, plant extracts, and combinations thereof, withoutdeparting from the scope of the invention. Nevertheless, operation usingthe much shorter hydrocarbon length gasoline is preferred in manyapplications over diesel fuel since it produces virtually no carbonparticulate matter.

Referring to FIG. 6, a preferred heat catalyzed injector-ignition fuelinjector 30 of the invention comprises a heated catalyzed all-in-oneinjector-ignition injector including a fuel input 44, an input fuelmetering system 46, electrical connectors 48, a nozzle pin valve driver50, a pressurization ram driver 52, an optional air inlet pinhole 54, amounting flange 56, a hot section 58 and an injector nozzle 60. Theinjector-ignition fuel injector 30 supports the vaporization,pressurization, activation and dispensing of fuel in a real worldmaintenance free environment. A characteristic operating pressure forthe injector-ignition fuel injector 30 of the invention is approximately100 bar dispensing into a 20:1 compression ratio engine (20 bar) with afuel load which produces a 40 bar peak. In a preferred implementation,the fuel injector 30 features an internal nickel molybdenum catalystthat is disposed within the hot section 58 of the fuel injector 30 nearthe injector nozzle 60. The catalyst may be activated by operating theinjector body at a temperature of approximately 750° F. Of course, aswould be appreciated by those of ordinary skill in the art, othercatalysts and injector operating temperatures may be employed withoutdeparting from the scope of the invention.

Referring to FIG. 7, the input fuel metering system 46 of theinjector-ignition fuel injector 30 of the invention will now bedescribed. Specifically, the input fuel metering system 46 includes aninline fuel filter 66 for filtering the fuel, a metering solenoid 68 formetering a next fuel charge comprising a predetermined amount of fuel,and a liquid fuel needle valve 70 for dispensing the next fuel chargeinto a pressurizing chamber 72 of the fuel injector 30. The liquid fuelneedle valve 70 preferably comprises an electromagnetically orpiezoelectric activated needle valve that dispenses the next fuel chargeinto the pressurizing chamber 72 in response to a look ahead computercontrol algorithm in the ECU of the internal combustion engine. Theinput fuel metering system 46 may accept fuel from a standard gasolinefuel pump or common rail distribution system.

With further reference to FIG. 7, the injector nozzle 60 of the fuelinjector 30 is disposed between the pressurization chamber 72 and thecombustion chamber 28 of the vehicle. The fuel charge dispensed by theinput fuel metering system 46 is roasted in the pressurization chamber72 via a hot section 58 of the fuel injector 30 surrounding the chamber72. More particularly, the fuel charge is heated in the pressurizationchamber 72 under pressure and in the presence of catalysts, which beginto crack the fuel and cause it to react with internal sources of oxygen.The injector nozzle 60 comprises an injector nozzle pin valve 74, acollimator 75, and a pin valve actuator 71. Specifically, the nozzle pinvalve 74 opens at approximately top dead center (180° of cyclerotation), allowing the hot pressurized gas into the combustion chamber28. The pin valve actuator 71 may comprise a pin valve solenoid whichoperates a pin valve drive shaft 118 for injecting the next fuel chargethrough the injector nozzle pin valve 74.

In the all-in-one fuel injector embodiment, the pin valve drive shaft118 is located inside the bore of the pressurization ram 92 such that itmay slide coaxially within the pressurization ram 92. However, the pinvalve drive shaft 118 operates independently of the pressurization ram92. An O-ring seal 119 on the top of the pressurization ram 92 blocksthe leakage path between these two shafts. The geometry of the injectornozzle 60 varies substantially from a typical liquid fuel injectornozzle in that the injector nozzle 60 includes the pin valve 74 and acollimator 75 for collimating the heated fuel and dispensing acollimated, relatively low pressure charge of hot gas into the cylinder.Specifically, the injector nozzle 60 of the fuel injector 30 iselectrically heated, for example using a conventional nichrome heatingelement 114 that lines the injector nozzle 60.

The pin valve actuator 71 of the injector nozzle 60 may comprise a rapidresponse electromagnetic drive or a piezoelectric drive. In its simplestform, the injector nozzle pin valve 74 opens to 100% as thepressurization ram 92 pushes the entire column of hot gas from thepressurizing chamber 72 into the combustion chamber 28 to fulldisplacement of the injector volume. As would be understood by one ofordinary skill in the art, many combinations of pin valve and ram drivemodulation may be employed with analog drive signals and/or digitalpulse signals to produce various heat release profiles under differentthrottle and load situations, without departing from the scope of thepresent invention.

Referring to FIGS. 8A and 8B, another component of the injector-ignitionfuel injector 30 comprises a pressurization ram system comprising thepressurization ram 92, the pressurization ram driver 52 and the hotsection 58 of the fuel injector 30 for heating the next fuel charge inthe pressurization chamber 72 prior to injection. In particular, FIG. 8Adepicts a first configuration of the pressurization ram system, whereinthe pressurization ram 92 is in a full displacement position.

FIG. 8B depicts a second configuration of the pressurization ram system,wherein the pressurization ram 92 is in a fully retracted position forallowing liquid fuel to enter the pressurization chamber 72. Thepressurization ram 92 compresses the fuel as it transitions from aliquid to a gas, and then to its critical point and beyond, where itbecomes a very dense vapor. The pressurization ram 92 comprises amagnetically active portion 96 disposed substantially within thepressurization ram driver 52, an insulating portion 97 and a hot sectioncompatible portion 98 which is disposed substantially within the hotsection 58 when the pressurization ram 92 is in the full displacementposition. The rest position for the pressurization ram 92 is at fulldisplacement as illustrated in FIG. 8A. The pressurization ram 92 mayfurther comprise one or more of O-ring seals 100 for preventing fluidleakage.

With continued reference to FIG. 8B, when the pressurization ram 92 isretracted, it forms a partial vacuum in the pressurization chamber 72,thus allowing the input fuel metering system 46 to inject the nextcharge as a relatively cool liquid. The pressurization ram 92 has arelatively long stroke and may incorporate a heat shield region forprotecting the input fuel metering system 46 from the high temperaturesnear the hot section 58. A multiple winding solenoid coil system 106,108 disposed within the pressurization ram driver 52 includes aretraction solenoid 106 and a pressurization solenoid 108. The multiplewinding solenoid coil system 106, 108 may be replaced by a linearstepping motor that is used to drive the pressurization ram 92.

The fuel injector 30 of the invention is inherently safe in that it onlyrequires a single firing of fuel above the auto-ignition temperature,which may be contained in a robust metal housing directly connected tothe engine cylinder (where combustion normally occurs). In this manner,the hot section 58 of the fuel injector 30 can be considered as a mereextension of the existing engine combustion chamber 28. By way ofexample, the hot section 58 of the fuel injector 30 may be electricallyheated via a conventional nichrome heating element 116 which lines thehot section 58.

Under electronic control of the ECU, a sufficient magnetic field isapplied to pressurize the fuel load to a predetermined levelcommensurate with the next firing, as specified by the operator'sthrottle position. The fuel charge is roasted in the pressurizationchamber 72 (via hot section 58) under pressure in the presence ofcatalysts, which begin to crack the fuel and cause it to react withinternal sources of oxygen. Such internal oxygen sources are present inconventional pump gas via included anti-knock agents and winteroxygenators such as MTBE and/or ethanol. Diesel fuels also commonlyinclude oxygen sources in the form of cetane boosters. According to theinvention, hot section catalysts may include without limitation: (1)nickel; (2) nickel-molybdenum; (3) alpha alumina; (4) aluminum silicondioxide; (5) other air electrode oxygen reduction catalysts (e.g., asused in fuel cell cathodes and metal air battery cathodes); and (6)other catalysts used for hydrocarbon cracking.

According to a preferred implementation, the operating temperature ofthe hot section 58 is approximately 750° F., which substantiallyminimizes the corrosion and heat-related strength loss of commonstructural materials such as 316 stainless steel and oil hardened toolsteel. In contrast, typical compression ignition operating temperaturesare above 1000° F. The hot section 58 may further comprise a nichromeheating wire. According to additional embodiments, oxygen may be pumpedinto the hot section 58 of the fuel injector 30.

Referring again to FIG. 7, the injector-ignition fuel injector 30 maypull in hot exhaust gas during the exhaust cycle of the engine byopening the injector nozzle pin valve 74 and retracting thepressurization ram 92. Under normal circumstances, the hot exhaust gaswill still have un-reacted oxygen, which can be optionally used inconjunction with the fuel's internal oxygenation agents to lightlyoxidize the fuel. Additionally, the fuel injector 30 may be configuredto include an air inlet pinhole 54 in communication with thepressurization chamber 72 such that additional oxygen in the form offresh air can be added to the hot section 58 when the pressurization ram92 is disposed in the fully retracted position. The air inlet pinhole 54may be equipped with a one way valve such as a ball valve (not shown) topreclude fuel vapor leakage during the pressurization stroke.Additionally, various other forms of air may be employed such as exhaustgas.

According to some embodiments of the invention, heated catalyzed thefuel injector 30 is inherently self-purging and self-cleaning.Specifically, the pressurizing ram 92 and the nozzle pin valve driveshaft 118 can be exercised repeatedly during engine starting operations,thereby (i) allowing air and moisture from long term engine stand to bepurged on start, and (ii) allowing any carbon build up to be flushedthrough the relatively large injector nozzle 60. Unlike conventionalfuel injectors, the pressurizing ram 92 moves over a relatively longstroke distance (0.25 inches or more) and can eliminate any void volumein the nozzle area 74 in its fully extended position.

In a preferred embodiment of the invention, the ECU may control one ormore heated catalyzed injector-ignition fuel injectors 30 of theinvention using a one firing cycle look-ahead algorithm forinjector-ignition operation. The look-ahead algorithm for controllinginjector-ignition timing may be implemented using a computer softwareprogram residing on the ECU, the software program comprising machinereadable or interpretable instructions for controlling fuel injection.According to the look-ahead algorithm, preparation for the next enginefiring starts immediately upon completion of the last engine firing. Atthis time, the fuel injector 30 is substantially empty of fuel, thepressurization ram 92 is in the full displacement position, the injectornozzle pin valve 74 is closed, and the hot section 58 is substantiallyat its operating temperature. In the simplest form of control, the ECUcompares the throttle input to prior settings such as last throttleinput, engine load, RPM, air inlet temperature, and other settings andelectronic fuel controls. Using this information, the ECU determines thefuel load and the estimated time to the next firing.

The next firing cycle commences after an appropriate delay to minimizethe fuel hold time in the hot section 58, thus minimizing excessivecracking of the fuel. Initially, the next firing cycle involvesretracting the pressurization ram 92, which allows the input fuelmetering system 46 to dispense an aerosol of liquid fuel into the hotsection 58. The pressurization ram 92 then pressurizes the fuel in a twostep cycle, including (i) protecting the input liquid fuel injector 30while the fuel is heating and vaporizing, and (ii) pressurizing the fuelto the target injection pressure and temperature. In the second step,the fuel is vaporized to reach the target injection pressure andtemperature.

After a pre-determined hold time, the injector nozzle pin valve 74 opensand the pressurization ram 92 pushes the fuel vapor column into thecombustion chamber 28, such that the pressurization ram 92 reaches thefull displacement position illustrated in FIG. 8A. In some embodiments,the pre-determined hold time may be back projected from the next topdead center event. The injector nozzle pin valve 74 then closes and theheated catalyzed fuel injector 30 is now ready for a next firingcommand. A wide range of variants with respect to the fuel injectorcycle (e.g., interactive operation of the pressurization ram 92 and theinjector nozzle pin valve 74 to tailor specific heat release profiles)are possible without departing from the scope of the invention. Sincethe main portion of the power stroke is merely a 30° rotation of a 720°four stroke cycle, the actual injection takes only approximately 4% ofthe available operating time.

In operation, fuel exposure time to the heated catalyst in the presenceof available oxygen sources (e.g., dissolved air or oxygenators such asethanol) within the pressurization chamber 72 is precisely controlled bythe ECU. This exposure time, which may be referred to herein as “thepre-oxidation hold time”, is critical to the proper operation of thefuel injector 30. For example, if the pre-oxidation hold time is toolong and/or at too high a temperature, the fuel will begin to crack intoshorter chain molecules and residual carbon. Such free carbon residue inthe form of black deposits can contaminate the fuel injection system. Onthe other hand, if the pre-oxidation hold time is too short and/or attoo low a temperature, insufficient pre-oxidation of the fuel mayresult, or no pre-oxidation at all.

At the cold extreme, the fuel injector 30 of the invention performs likea conventional diesel compression ignition fuel injector with relativelylong ignition delays (e.g., in the range of 5-10 ms at 1800 RPM and 20:1compression). Cold injection conditions result in reduced efficiencybecause the injection point must occur well ahead of top dead center toinitiate combustion, thus generating push back and waste heat in thecylinder. In addition, low cetane rated fuels such as heptane, octane,and ethanol may not fire at all or will fire erratically under such coldinjection conditions, as is typical of their behavior when used inconventional diesel engines.

The following example illustrates how optimal pre-oxidation hold timeconditions may be determined in a laboratory engine. In particular, alaboratory test engine with 220 cm3 displacement and 23:1 compressionwas outfitted with a heated catalyzed fuel injector 30 as disclosedherein, and utilizing a fuel mixture of approximately 65 parts heptane,25 parts cetane and 10 parts ethanol by volume. During testing, theengine was operated at 1800 RPM at approximately 1 horsepower grossoutput. In addition, the catalyst lining the inside of the hot section58 consisted of nickel with about 5% molybdenum. A preferred catalyticheating temperature was determined to be approximately 720° F., whichproduced the lowest exhaust gas temperature and minimal carbon residueformation within the injector body.

The ignition delay of the fuel injector 30 was determined by comparing alaser based injector pin position indicator against a standardcommercial Delphi knock sensor. Specifically, ignition delays of 100microseconds or less (i.e., one degree of crank angle or less) werefound at 1800 RPM. Increasing the catalytic heating temperature to about800° F. caused rapid carbon build up which quickly impeded fuel flow,whereas reducing the catalytic heating temperature to below about 720°F. lengthened the ignition delay time and reduced engine power outputdue to the necessity of advancing the injection point well ahead of topdead center. At room temperature, this fuel mixture (i.e., 65% heptane,25% cetane and 10% ethanol) would not fire in the test engine at allwithin the limits of the ignition advance allowed by the test systemelectronics (approximately 8 milliseconds). Fuel flow during testing wasin the range of 3 cm³ to 5 cm³ per minute, while the hot section of theinjector tip was approximately 2 cm long with a cross sectional area of0.043 cm². Injector pressure was 1200 psi such that the fuel mixture wasoperating as a super-critical fluid at the optimal temperature setting(the critical temperature for heptane is about 512° F., and the criticalpressure is about 397 psi).

In addition to the conventional parameters which affect fuel flow in anengine, the fuel injection system of the invention has particularsensitivities to fuel composition due to the use of the fuel as asuper-critical fluid with a pre-oxidation heated catalytic stage, whichmakes the fuel sensitive to fuel cracking based carbon build up. Inaddition, since the fuel injector 30 may run on both high octane andhigh cetane rated fuels as well as mixtures of gas engine fuels anddiesel engine fuels, the fuel delivery system is subjected to a muchbroader range of operating parameters than conventional gasoline (sparkignition) or diesel (compression ignition) engines. For example, variousfuels may include a wide range of boiling points, critical pressures,critical temperatures, and susceptibility to thermal cracking. Inaddition, the fuel densities may range from 0.6 forpentane/hexane/heptane mixtures to well above 0.9 for some biodieselformulations. Accordingly, usable fuel mixtures may span a broad rangeof fuel densities and various other catalytic sensitivities.

In view of the various fuel mixtures, the ECU utilizes conventionaloperating factors such as engine RPM and load to adjust fuel flow.Additionally, the ECU performs a look-ahead calculation to determine theoptimal pre-oxidation hold time for the selected fuel mixture. Theminimal pre-oxidation hold time is limited by the mechanical responsetime of the fuel injection system, which is typically in the range of2-3 milliseconds. The maximum pre-oxidation hold time (for a one cyclelook-ahead for a four stroke engine at 1800 RPM) is about 66.6milliseconds (i.e., the approximate duration between firings). Inaddition to controlling fuel injection into the catalytic hot section,the ECU may also adjust the energy input into the hot section such thatthe fuel is heated to the designated temperature more rapidly at higherthrottle settings than at lower throttle settings. However, the thermaltime constants for such fuel injection systems are typically in therange of tenths of a second or higher (i.e., several firing cycles). Inaddition, if waste heat is utilized to reduce the electrical input tothe heater (e.g., using active/passive heat pipes from the exhaustarea), the thermal time constant will be even longer.

All practical engines have substantial rotary inertia which generallyrequires tenths of a second to seconds to overcome while changing fromone RPM setting to another. According to some embodiments of theinvention, additional look-ahead delays may be employed under certainthrottle changes to accommodate further energy input. Also, the thermalinput may be ramped electrically to accommodate new fuel flows. By wayof example, during acceleration in a conventional automobile, thepre-oxidation hold time may be increased from a maximum of one cycle totwo, three or even four cycles, by building up excess fuel in the hotsection (e.g., by pumping fuel in faster than the fuel injector pinrelease rate). Under these conditions, thermal energy input can beramped to bring the system back into a one cycle look-up delay. Thecontrol scenario is simpler on deceleration since fuel hold times can bedropped by a ratio of at least 30:1 at 1800 RPM (i.e., 66 millisecondsto 2 milliseconds).

Engine responsiveness using the fuel injector 30 of the invention varieswidely by application. For example, a high performance sports car orrace car is expected to have very fast throttle response.Injector-ignition systems in such applications may incorporateadditional features to accommodate rapid throttle changes with minimalrisk of carbon formation within the injector hot section. At the otherextreme, a large stationary power generator which precisely maintains 60Hz AC at a fixed output (e.g., about 1800 RPM), may have very slowlychanging throttle inputs, and therefore may be able to utilize asimplified form of the heated catalyzed fuel injection system of theinvention.

The ECU of the internal combustion engine is capable of properlyidentifying the fuel mixture in use and then identifying appropriatepre-oxidizer hold time settings in an ECU database for its operation. Infuel injection systems that are restricted to conventional pumpgasoline, this can be readily accomplished by pre-loading a table intothe ECU database spanning the range of fuel octane ratings andoxygenator additives (e.g., MTBE, ethanol, other octane and cetaneboosters, and other fuel oxygenator agents) that will be encounteredwithin the vehicle's designated regional marketing operating area (i.e.,US spec versus Canadian spec versus European spec, etc.). The ECU maycontinuously tune its operation over this range of fuels by sensing theignition delay. This is typically done today in modern diesel engines bycomparing the actual injector opening position via a position sensoragainst a commercial engine knock sensor or, in some specialized cases,against an in-cylinder absolute pressure sensor.

A supplemental input to the ECU may be necessary to accommodate the widerange of fuels and mixtures for systems featuring flex fuelinjector-ignition capability. For example, fuels containing a highpercentage of ethanol and fuels which contain high cetane ratings (e.g.,conventional diesel, biodiesel or vegetable oils) may require fuelmixture information, particularly when mixed with conventional gasolinesat the fuel delivery pump or in the engine fuel tank. According to someembodiments of the invention, this information is provided using adirect entry scheme at fueling, as described hereinabove. Otherembodiments utilize an on-board analyzer which samples the fuel on boardand communicates engine operating parameters to the ECU.

The heated catalyzed fuel injection system disclosed herein may behighly sensitive to ignition timing. During operation, waste heat isminimized by initiating a very rapid burn ignition substantially at topdead center and completing the burn at a predetermined time to reducewaste heat losses (out the exhaust valve), increase power strokeproduction, and decrease fuel combustion noise. An injector-ignitionsystem that is optimized in this manner may operate at very highcompression (e.g., in the range of 20:1 to 40:1). It may be desirable insome applications to use the fuel injectors 30 of the invention in alight weight engine with a minimal flywheel and, thus, minimalrotational inertia.

In injector ignition equipped 1, 2, 3 or, 4 cylinder engines,compression braking (which occurs as the piston approaches top deadcenter) is a significant factor in engine timing. Conventional ECUtiming algorithms tend to fire very early in this application becausethey do not accommodate the rapid deceleration which occurs near topdead center in this class of engine. Additionally, any real world fuelinjector has a mechanical delay from the time the electrical fire signalis given to the time it injects fuel into the cylinder. Such mechanicaldelays are typically in the range of 1 to 3 milliseconds. To compensatefor this mechanical delay, the ECU of the invention adjusts the timingof the injector fire signal when the engine is rapidly decelerating dueto compression braking. In addition, a look-up table may be added to theECU database which corrects for engine deceleration over a predeterminedoperating map including RPM, engine load, and engine load trend, i.e.,deceleration or acceleration rates. The engine table may be pre-loadedwith a learning algorithm to measure the error in predicted top deadcenter versus actual top dead center for this class of engine geometry.The table may be dynamically adjusted in operation through use of alearning algorithm which continually adjusts the table entries bycomputing the difference between an injection pin location indicator andan absolute top dead center indicator. This adjustment may be refinedusing knock sensor input, or using an in cylinder pressure sensor whichdetects absolute fire position versus top dead center.

It should be evident to one skilled in the art that timing adjustmentsto correct for compression braking can readily interfere with timingadjustments required for different grade fuels in conjunction withpre-oxidizer hold time requirements. The ECU of the invention mayutilize pattern recognition heuristics such as the identification of asteady state throttle and load condition to fine tune the ignition delaydrift due to compression braking. Such fine tuning is separate anddistinct from the conventional tuning that is typically required withrespect to varying fuel mixtures.

With further reference to FIG. 7, the energy required to operate theinjector nozzle 60 may theoretically be as little as two percent of theenergy content of the drive fuel; however, practical engine designconsiderations such as size constraints on high temperature insulationcould cause the heating requirements to rise to several percent of shaftoutput power if driven solely by electrical system power. Since the fuelinjector 30 is immediately next to one or more engine exhaust portsduring operation, a very effective source of waste heat is readilyavailable. The fuel injector 30 of the invention may be housed directlyin an exhaust port of a multi-valve engine where the flow through theexhaust valve may be selectively controlled. In addition, various activeand/or passive heat pipe geometries that bring in heat from the exhaustzone may be utilized to reduce the electrical input to the heater.

Various automobiles may use three or more types of injectors in theirdirect injection gasoline power plant, including: (1) throttle bodyinjectors for idling; (2) common rail intake port injectors for lowspeed operation; and (3) direct injectors for high speed operation.Likewise, the fuel injector 30 described herein may be used alone or ina wide range of combinations with throttle body and common railinjectors, with or without selectively operated spark ignition sources.Additionally, the fuel injector 30 may operate in a pure vapor mode ormay dispense a mixture of vapor and liquid. In applications where highRPM and high loading are infrequent (e.g., for a typical economy car),it may be desirable to use a fuel injector with a relatively low thermalheating capability, such that pure vapor operation is limited to vehiclecruise operation, for example under about 3600 RPM. Such a fuel injectorprogressively passes more liquid above a predetermined throttle loadsetting, resulting in progressively lower efficiency operation but atmuch higher power levels than the pure vapor design point.

Referring to FIG. 9, in accordance with an alternative embodiment of theinvention, the all-in-one fuel injector geometry described above isunfolded into a heated catalyzed linear fuel injector 30′ comprising aliquid fuel metering system 46′, a retraction solenoid 106′, apressurization solenoid 108′, pressurization ram 92′, an injector nozzle60′, a pin valve drive solenoid 71′, a nozzle pin valve drive shaft 118′and a hot section 58′. This fuel injector configuration simplifies therather complex and precise requirements of the coaxial placement of thepin valve drive shaft 118′ inside the pressurization ram 92′. In otherwords, the pin valve drive shaft 118′ is not disposed within thepressurization ram 92′ and does not slide coaxially within the pin valvedrive shaft 118′. Instead the pressurization ram 92′ is disposed at anangle with respect to the pin valve drive shaft 118′ as depicted in FIG.9. It is noted, however, that this linear configuration reduces theself-purging and self-cleaning effectiveness of the all-in-one geometryin that the pressurization ram 92′ is now off to one side and can nolonger clean and purge the void volume around the injector nozzle 60′.This configuration utilizes the same ECU timing as the all-in-oneinjector depicted in FIGS. 7 and 8. In operation, a fuel chargedispensed by the input fuel metering system 46′ is roasted via hotsection 58′ under pressure and in the presence of catalysts, which beginto crack the fuel and cause it to react with internal sources of oxygen.At approximately top dead center, the pin valve drive shaft 118′ injectsthe hot pressurized gas into the combustion chamber via the injectornozzle 60′.

Both the all-in-one fuel injector 30 and the linear injector 30′ may beoperated at higher RPM and smaller physical size by replacing the liquidbased input fuel metering system with a medium pressure, mediumtemperature feed system. This system, which may be shared among all theinjectors on the engine, may utilize a medium pressure pump (e.g., inthe 500 PSI range) and a pre-heating coil for maintaining fuel in vaporform at a sufficiently low temperature (e.g., 400° F.) to minimizehydrocarbon cracking and degradation. In operation, the pre-heated,pre-vaporized fuel charge is introduced into either of the aboveinjector configurations at the inlet point of the drive ram, therebyreducing the ram's required displacement, size, and heat input, thusallowing higher speed operation.

According to additional embodiments of the invention, theabove-described medium pressure pump may be replaced by an external highpressure liquid feed pump that feeds the pre-heating coil through a oneway valve. Small diameter capillary tubing and fittings may be used toreduce the volume in the hot section. The system may be purged on shutdown to minimize the build up of carbon from excessively cracked fuels.Various combinations of components of the above described pumpembodiments may be combined. For example, the number of stages ofpumping and placement of pumps can vary widely based on engine size,number of cylinders, fuel recovery system geometry and other factors.

Thus, it is seen that an injector-ignition fuel injector for an internalcombustion engine is provided. One skilled in the art will appreciatethat the present invention can be practiced by other than the variousembodiments and preferred embodiments, which are presented in thisdescription for purposes of illustration and not of limitation, and thepresent invention is limited only by the claims that follow. It is notedthat equivalents for the particular embodiments discussed in thisdescription may practice the invention as well.

While various embodiments of the present invention have been describedabove, it should be understood that they have been presented by way ofexample only, and not of limitation. Likewise, the various diagrams maydepict an example architectural or other configuration for theinvention, which is done to aid in understanding the features andfunctionality that may be included in the invention. The invention isnot restricted to the illustrated example architectures orconfigurations, but the desired features may be implemented using avariety of alternative architectures and configurations. Indeed, it willbe apparent to one of skill in the art how alternative functional,logical or physical partitioning and configurations may be implementedto implement the desired features of the present invention. Also, amultitude of different constituent module names other than thosedepicted herein may be applied to the various partitions. Additionally,with regard to flow diagrams, operational descriptions and methodclaims, the order in which the steps are presented herein shall notmandate that various embodiments be implemented to perform the recitedfunctionality in the same order unless the context dictates otherwise.

Although the invention is described above in terms of various exemplaryembodiments and implementations, it should be understood that thevarious features, aspects and functionality described in one or more ofthe individual embodiments are not limited in their applicability to theparticular embodiment with which they are described, but instead may beapplied, alone or in various combinations, to one or more of the otherembodiments of the invention, whether or not such embodiments aredescribed and whether or not such features are presented as being a partof a described embodiment. Thus the breadth and scope of the presentinvention should not be limited by any of the above-described exemplaryembodiments.

Terms and phrases used in this document, and variations thereof, unlessotherwise expressly stated, should be construed as open ended as opposedto limiting. As examples of the foregoing: the term “including” shouldbe read as meaning “including, without limitation” or the like; the term“example” is used to provide exemplary instances of the item indiscussion, not an exhaustive or limiting list thereof; the terms “a” or“an” should be read as meaning “at least one,” “one or more” or thelike; and adjectives such as “conventional,” “traditional,” “normal,”“standard,” “known” and terms of similar meaning should not be construedas limiting the item described to a given time period or to an itemavailable as of a given time, but instead should be read to encompassconventional, traditional, normal, or standard technologies that may beavailable or known now or at any time in the future. Likewise, wherethis document refers to technologies that would be apparent or known toone of ordinary skill in the art, such technologies encompass thoseapparent or known to the skilled artisan now or at any time in thefuture.

A group of items linked with the conjunction “and” should not be read asrequiring that each and every one of those items be present in thegrouping, but rather should be read as “and/or” unless expressly statedotherwise. Similarly, a group of items linked with the conjunction “or”should not be read as requiring mutual exclusivity among that group, butrather should also be read as “and/or” unless expressly statedotherwise. Furthermore, although items, elements or components of theinvention may be described or claimed in the singular, the plural iscontemplated to be within the scope thereof unless limitation to thesingular is explicitly stated.

The presence of broadening words and phrases such as “one or more,” “atleast,” “but not limited to” or other like phrases in some instancesshall not be read to mean that the narrower case is intended or requiredin instances where such broadening phrases may be absent. The use of theterm “module” does not imply that the components or functionalitydescribed or claimed as part of the module are all configured in acommon package. Indeed, any or all of the various components of amodule, whether control logic or other components, may be combined in asingle package or separately maintained and may further be distributedacross multiple locations.

Additionally, the various embodiments set forth herein are described interms of exemplary block diagrams, flow charts and other illustrations.As will become apparent to one of ordinary skill in the art afterreading this document, the illustrated embodiments and their variousalternatives may be implemented without confinement to the illustratedexamples. For example, block diagrams and their accompanying descriptionshould not be construed as mandating a particular architecture orconfiguration.

1. An injector-ignition fuel injection system for dispensing fuel into acombustion chamber of an internal combustion engine, the fuel injectionsystem comprising: an ECU controlling a heated catalyzed fuel injectorfor heating and catalyzing a next fuel charge, wherein the ECU uses aone firing cycle look-ahead algorithm for controlling fuel injection. 2.The fuel injection system of claim 1, wherein the look-ahead algorithmcomprises a computer software program residing on the ECU, the softwareprogram comprising machine readable or interpretable instructions forcontrolling fuel injection.
 3. The fuel injection system of claim 1,wherein the algorithm compares a current throttle input to prior enginedata and determines a fuel load and an estimated time to the nextfiring.
 4. The fuel injection system of claim 3, wherein the priorengine data comprises a last throttle input, an engine load, an RPMvalue, and an air inlet temperature.
 5. The fuel injection system ofclaim 1, wherein the next fuel charge comprises a mixture ofapproximately 65% heptane, 25% cetane, and 10% ethanol by volume.
 6. Thefuel injection system of claim 1, wherein the fuel charge is heated andcatalyzed in the presence of one or more oxygen sources.
 7. The fuelinjection system of claim 1, wherein the algorithm controlspre-oxidation hold time within a pressurization chamber of the fuelinjector.
 8. The fuel injection system of claim 7, wherein the algorithmidentifies appropriate pre-oxidizer hold time settings in an ECUdatabase based upon a predetermined fuel mixture in use.
 9. The fuelinjection system of claim 8, wherein the ECU database contains apre-loaded table spanning a range of fuel octane ratings and oxygenatoradditives that may be encountered.
 10. The fuel injection system ofclaim 9, wherein the oxygenator additives are selected from the groupconsisting of MTBE, ethanol, other octane and cetane boosters, and otherfuel oxygenator agents.
 11. The fuel injection system of claim 9,wherein the ECU continuously tunes its operation over the range of fueloctane ratings by sensing ignition delay.
 12. The fuel injection systemof claim 1, wherein the fuel charge is catalyzed using a catalystselected from the group consisting of nickel, nickel-molybdenum, alphaalumina, aluminum silicon dioxide, other air electrode oxygen reductioncatalysts, and other catalysts used for hydrocarbon cracking.
 13. Thefuel injection system of claim 1, wherein the fuel charge is catalyzedusing a catalyst comprising nickel with about 5% molybdenum.
 14. Thefuel injection system of claim 1, wherein the catalytic heatingtemperature is between 600° F. and 750° F.
 15. The fuel injection systemof claim 1, wherein injector pressure is high enough that the fuelcharge operates as a super-critical fluid at a selected temperaturesetting.
 16. The fuel injection system of claim 1, wherein the fuelinjector runs on high octane rated fuels, high cetane rated fuels, andmixtures of gas engine fuels and diesel engine fuels.
 17. The fuelinjection system of claim 1, wherein the algorithm controls the fuelinjector to dispense the fuel charge substantially exclusively during apower stroke of the internal combustion engine.
 18. The fuel injectionsystem of claim 1, wherein preparation for a next engine firing startsimmediately upon completion of a last engine firing wherein the fuelinjector is substantially empty of fuel.
 19. The fuel injection systemof claim 1, wherein the algorithm adjusts energy input into the fuelinjector such that the fuel is heated to a selected temperature morerapidly at higher throttle settings than at lower throttle settings. 20.The fuel injection system of claim 19, wherein the algorithm allows upto four firing cycles of fuel to build up in the hot section to increasefuel heating exposure time during rapid acceleration.
 21. The fuelinjection system of claim 1, wherein the ECU includes a supplementalinput for receiving fuel mixture information to accommodate a range offuels and fuel mixtures.
 22. The fuel injection system of claim 21,wherein the fuel mixture information is provided using a direct entryscheme at fueling or using an on-board analyzer which samples the fuelon board and communicates engine operating parameters to the ECU. 23.The fuel injection system of claim 1, wherein waste heat is minimized byinitiating a rapid burn ignition substantially at top dead center. 24.The fuel injection system of claim 1, wherein the ECU adjusts aninjector fire signal to compensate for rapid rotational decelerationthat occurs just before top dead center in high compression engines. 25.The fuel injection system of claim 24, wherein the ECU includes anengine look-up table which corrects for engine deceleration over apredetermined operating map including RPM, engine load, and engine loadtrend.
 26. The fuel injection system of claim 25, wherein the enginelook-up table is pre-loaded with a learning algorithm to measure theerror in predicted top dead center versus actual top dead center for aparticular class of engine geometry.
 27. The fuel injection system ofclaim 25, wherein the engine look-up table is dynamically adjusted inoperation through use of a learning algorithm which continually adjuststable entries by computing the difference between an injection pinlocation indicator and an absolute top dead center indicator.
 28. Thefuel injection system of claim 27, wherein the adjustment is refinedusing knock sensor input, or using an in cylinder pressure sensor whichdetects absolute fire position versus top dead center.
 29. The fuelinjection system of claim 1, wherein the ECU utilizes patternrecognition heuristics to fine tune ignition delay drift due tocompression braking.
 30. The fuel injection system of claim 29, whereinthe pattern recognition heuristics provide for the identification of asteady state throttle and load condition.
 31. An injector-ignition fuelinjection system for dispensing fuel into a combustion chamber of aninternal combustion engine, the fuel injection system comprising: an ECUcontrolling a heated catalyzed fuel injector for heating and catalyzinga next fuel charge, wherein the ECU uses a one firing cycle look-aheadalgorithm for controlling fuel injection; wherein the heated catalyzedfuel injector comprises: an input fuel metering system for dispensing anext fuel charge into a pressurizing chamber; a pressurization ramsystem including a pressurization ram for compressing the fuel chargewithin the pressurizing chamber, wherein the fuel charge is heated inthe pressurization chamber in the presence of a catalyst; and aninjector nozzle for injecting the heated catalyzed fuel charge into thecombustion chamber of the internal combustion engine.
 32. The fuelinjection system of claim 31, wherein preparation for a next enginefiring starts immediately upon completion of a last engine firing. 33.The fuel injection system of claim 32, wherein upon completion of thelast engine firing, the fuel injector is substantially empty of fuel,the pressurization ram is in a full displacement position, and theinjector nozzle is closed.
 34. The fuel injection system of claim 31,wherein a next firing cycle involves retracting the pressurization ram,which allows the input fuel metering system to dispense an aerosol ofliquid fuel into the pressurization chamber.
 35. The fuel injectionsystem of claim 34, wherein the pressurization ram then pressurizes thefuel in a two step cycle, including protecting the fuel injector whilethe fuel is heating and vaporizing, and pressurizing the fuel to atarget injection pressure and temperature.
 36. The fuel injection systemof claim 35, wherein the fuel is vaporized to reach the target injectionpressure and temperature.
 37. The fuel injection system of claim 31,wherein the injector nozzle opens after a predetermined hold time andthe pressurization ram pushes the fuel charge into the combustionchamber such that the pressurization ram reaches a full displacementposition.
 38. The fuel injection system of claim 37, wherein thepre-determined hold time is back projected from a next top dead centerevent.